What i want is information
on a turbocharged 13b.  The project is a mustang II,
retractable gear.  wanting about 200 hp with the turbo
normalizing at altitude.   I have a 91 turbo engine
and would like to start out with the mazda turbo.  The
more i read the more confused i get. Some  using a
wastegate, some not.  If a wastegate is used is a
muffler necessary.  Is tracy's cut down intake being
used for turbo system if not what works.  Could you
point me in the right direction for some answers.
Thanks for any help. Jim Coffman

For the power and torque curves for your 1991 13B Turbo engine with stock induction system
and stock turbocharger, refer to SAE paper 900036, "New Technology Employed for the Latest
13B-Rotary Engine".  Figure 2 has the curves. This paper was written by Mazda Corp.  At
6500 rpm, the engine puts out its max 200 hp.  It puts out it's max torque of 196 ft-lbs at
4000 rpm.

The best information I've found so far on turbocharging for aircraft engines is SAE paper
790608, "Selection of Aircraft Turbocharger Systems."

I have the same year and model engine you do, and am also interested in normalizing the
engine for altitude.  As far as normalizing for altitude, it depends on how high you want
to fly and have normalized power.  I haven't been able to find an engineering quality
compressor map for the stock turbocharger, so it's unclear just what the critical altitude
will be.  I like Paul L's plan to use the stock turbo and install a turbine rpm gauge.
He'll just monitor the turbine speed while flying at altitude and ensure it doesn't go
above critical rpm's.  He'll then see how much boost he can get.

I've been studying some compressor maps for turbos from Turbonetics.  They claim to have an
upgrade compressor to the stock turbocharger for $635 - the T04B Super V.  They machine out
your compressor housing and install a new compressor wheel.  They claim to have obtained 18
psi boost with this upgrade at maximum engine rpm (8000 rpm) and while at sea-level.  I
asked about their T04B Super H compressor, and they said the stock turbine assembly didn't
have enough power to drive this larger compressor wheel sufficiently to provide sufficient
boost levels.

I think that normal operation of the engine in the car at 6000 to 7000 rpm may provide
about 5 - 7 psi boost at sea-level with all stock induction system and turbocharger.
(Correct me if I'm wrong here, anyone.)  So if you're shooting for 14.7psi + 5psi = 19.7psi
total pressure at 7000 rpm, no one outside of Mazda knows how high up in altitude you can
maintain this.

I've done some initial calculations for the T04B Super V modification, using the one data
point Turbonetics gave me, and their compressor map, and have guessed the critical altitude
might be around 15,000 feet.  But, this is just a partially educated guess.  Please don't
go out buying or designing anything based on my guess.

A good book on turbochargers is by Hugh MacInnes, simply called "Turbochargers".

Hope this info helps.

Scott

 
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